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Saturday, January 12, 2013

Galactan and Biofuels

I suppose that the idea here is to increase the yield of galactan in
order to produce a viable feedstock for high quality fuel. Since the
model is some species of mustard, using canola can not be far behind.
It would be convenient to covert a ton of canola waste into a couple
hundred pounds of fuel feedstock.

Otherwise, I think that this is a long shot for the advertised
benefits and more pure research.

Then again, converting plant waste into useful feed-stocks is high on
the research agenda anyway. It allows us to jump past the oil
industry with superior green credentials.

Galactan is a polymer
of galactose, a six-carbon sugar that can be readily fermented by
yeast into ethanol and is a target of interest for researchers in
advanced biofuels produced from cellulosic biomass. Now an
international collaboration led by scientists at the U.S. Department
of Energy (DOE)'s Joint BioEnergy Institute (JBEI) has identified
the first enzyme capable of substantially boosting the amount of
galactan in plant cell walls.

Unlike ethanol,
advanced biofuels synthesized from the sugars in plant cells walls
could replace gasoline, diesel and jet fuels on a gallon-for-gallon
basis and be dropped into today's engines and infrastructures with no
modifications required.

Also, adanced biofuels
have the potential to be carbon-neutral, meaning they could be burned
without adding excess carbon to the atmosphere. Among the key
challenges to making advanced biofuels cost competitive is finding
ways to maximize the amount of plant cell wall sugars that can be
fermented into fuels.

"We have
confirmed the identity of the GT92 enzyme as the first enzyme shown
to increase the biosynthesis of galactan," says Henrik Scheller,
vice president for JBEI's Feedstocks Division and director of its
Cell Wall Biosynthesis group. "This identification of the first
B-1,4-galactan synthase provides an important new tool for the
engineering of advanced bioenergy fuel crops."

Scheller, who also
holds an appointment with DOE's Lawrence Berkeley National Laboratory
(Berkeley Lab), is the corresponding author of a paper in the journal
Plant Cell that describes this work.

The paper is titled
"Pectin Biosynthesis: GALS1 in Arabidopsis thaliana is a
B-1,4-Galactan B-1,4-galactosyltransferase." Co-authors were
JBEI's April Liwanag, Berit Ebert, Yves Verhertbruggen, Emilie
Rennie, Carsten Rautengarten, and Ai Oikawa, plus Mathias Andersen
and Mads Clausen of the Technical University of Denmark.

Galactans are
polysaccharide components of pectin, the sticky sugar substance that
binds together the individual cells in plant cell walls and is used
to make jellies and jams. The B-1,4-galactan component of pectin is
especially abundant in the "tension wood" that forms in
cell walls in response to mechanical stress from wind or snowfall.

"Galactans are
composed of hexoses, which in contrast to pentoses, are easily
utilized by fermenting microorganisms for the production of biofuels
and other compounds," Scheller says. "It would be
advantageous to develop plants with increased galactan content
instead of hemicelluloses consisting largely of pentoses."

GT92 is a family of
glycosyltransferase proteins whose genes are found in all plants that
have been genetically sequenced. An increased expression of GT92
genes has been observed in studies of tension wood.

This observation
combined with the knowledge that tension wood is rich in
B-1,4-galactan led Scheller and his colleagues to investigate the
function of GT92 proteins in Arabidopsis thaliana, a small flowering
relative of mustard that serves as a model organism for plant
studies.

Arabidopsis has three
members of GT92, which Scheller and his colleagues designated as
GALACTAN SYNTHASE 1,2 and 3 (GALS1, GALS2 and GALS3). While
loss-of-function mutants in all three genes were found to be galactan
deficient, Scheller and his colleague isolated and tested GALS1.

"Overexpression
of GALS1 resulted in plants with 50-percent higher B-1,4-galactan
content and no adverse phenotype," Scheller says. "We
expect that the results for GALS2 and GALS3 overexpressors will be
similar though we have yet to test them."

Given that all three
Arabidopsis GALS genes showed overlapping but not identical
expression, Scheller and his colleagues are now combining mutations
of GALS genes to better understand the role of B-1,4-galactan in
plants.

They're also carrying
out basic studies on these enzymes, including crystallization and
structural analysis. In addition, they're overexpressing the GALS
proteins in different combinations to determine if even higher
production of B-1,4-galactan results.

"As
B-1,4-galactan is an ancient invention, the function of GT92 as a
galactan synthase in Arabidopsis should also be applicable to
switchgrass, Miscanthus, poplar and other plants being considered as
crops for advanced biofuels," Scheller says. "We do not
anticipate any difficulty in being able to overexpress GT92 genes in
these plants."

This research was
funded by the DOE Office of Science, and by the Danish Strategic
Research Council.

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18 years old, having cleaned out my HS library, I concluded the only ambition worth having was becoming a great genius. An inner voice cheered. Yet it is my path I have shared much to the Human Gesalt. Mar 2017 - 4.56 Mil Pg Views, March 2013 - Posted my paper introducing CLOUD COSMOLOGY & NEUTRAL NEUTRINO described as the SPACE TIME PENDULUM. Sep 2010 -My essay titled A NEW METRIC WITH APPLICATIONS TO PHYSICS AND SOLVING CERTAIN HIGHER ORDERED DIFFERENTIAL EQUATIONS has been published in Physics Essays(AIP) June 2010 quarterly. 40 years ago I took an honors degree in applied mathematics from the University of Waterloo. My interest was Relativity and my last year there saw me complete a 900 level course under Hanno Rund on his work in Relativity. I continued researching new ideas and knowledge since that time and I have prepared a book for publication titled Paradigms Shift. I maintain my blog as a day book and research tool to retain data, record impressions, interpretations and to introduce new insights to readers.